Photovoltaic devices, devices that convert solar radiation directly to electricity, have been developed dramatically in the last 25 years. The majority of the development effort in the photovoltaic area originally was directed towards the development of crystalline photovoltaic devices. Single crystal devices, such as single crystal silicon solar cells, originate as thin wafers cut from a solid cylinder of crystalline silicon. These wafers are very fragile and must be protected from breakage. In many applications, these single crystal photovoltaic devices are intended to be interconnected, either in series or in parallel, and permanently deployed for power generation. It is necessary to encase these photovoltaic devices, either individually or in an array, in a rigid framework such as a metal casing and provide a rigid transparent cover material, such as glass to protect the devices. Such an encasing arrangement generally results in a heavy module assembly wherein the encasing, or support, means contributes disproportionately to the overall weight and cost of the photovoltaic device. The same is true for the development of polycrystalline photovoltaic devices.
More recently, photovoltaic devices have been developed that utilize amorphous materials. These amorphous aaterials, such as those disclosed in U.S. Pat. No. 4,217,374 entitled "Amorphous Semiconductor Equivalent to Crystalline Semiconductors" to Ovshinsky, et al. may be deposited on a flexible substrate material. Such amorphous materials do not share the fragile characteristics of their crystalline and polycrystalline counterparts, and so do not have to be as carefully protected. As an example, U.S. Pat. No. 4,410,558, entitled "Continuous Amorphous Solar Cell Production System" to Izu, et al. describes a method of making laminated flexible amorphous silicon solar cells. Such solar cells may incorporate a thin electrically conductive substrate such as stainless steel, amorphous silicon layers, and a transparent electrically conductive top contact of indium tin oxide, the resultant solar cells having a high degree of flexibility that does not impair the cells' efficiency.
Arrays of solar cells in accordance with U.S. Pat. No. 4,419,530, entitled "Solar Cell and Method of Producing Same" to Nath comprise strips of subcells interconnected in series and/or in parallel. An array of such solar cells may be laminated so as to form a flexible array capable of being rolled or similarly disposed for easy transport, unlike rigid crystalline or semicrystalline solar cell arrays.
When deployed in the field, an amorphous solar cell array does not require a protective glass cover as does crystalline or semicrystalline arrays, and so retains its flexibility. However, for permanent or semipermanent deployment, some degree of rigidity is desirable.
It is well known to fix fragile crystalline and semicrystalline cells in rigid frames so as to protect the individual solar cell and its protective transparent covering. Such support means include metal frames as discussed in U.S. Pat. No. 4,089,705 to Rubin, and fiber reinforced plastic support means as disclosed in U.S. Pat. No. 4,132,570 to Caruso, et al. Caruso, et al. teach a solar cell support made from an electrically non-conductive material having a plurality of interconnected wells in the top surface. each well adaptable to receive one crystalline solar cell. The support is designed to accept a glass top cover. The bottom of the support contains rib stiffeners to impart rigidity to the solar cell module.
What is lacking in the field of photovoltaic devices is a lightweight, semirigid support capable of accepting and retaining a f1exib1e photovoltaic module and imparting a high degree of rigidity to the assembly.
It is therefore one object of this invention to provide a semirigid photovoltaic module assembly.
It is another object of this invention to provide semirigid support means for the deployment of flexible photovoltaic modules.
These and additional objects of the present invention will be evident to one skilled in the art from the following description and drawings, and from the appended claims.